Screw-jack.



- G. T. STARBUGK.

SCREW JACK,

APPLIGATION FILED MAY 25, 1909.

Patented Sept. 6, 1910.

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M Gum/mu 0. T. STARBUGK.

SCREW JACK.

v APPLICATION FILED MAY 25, 1909. 969,215. Patented Sept. 6, 1910.

2 SHEETS-SHEET 2.

' 6, is a side elevation and edge view of .merges with theouter surface of CALVIN T. STABBUGK, 3F BIRMINGHAM, ALABAMA.

Specification of Letters Patent.

Application filed, may 25, 1809. Serial No. 498,184.

To all whom it may concern:

Be it known that I, CALVIN T. STARBUOK, a citizen of the United States of America, residing at Birmingham, in the county of Jefi'erson and State of Alabama, have invented certain new and useful improvements in Screw-Jacks, of which the following is a specification.

This invention relates to hoisting and particularly to a screw ack having anti-friction balls engaging the threads of the movable member.

An object of the invention is to provide novel means for intermittently arresting the jack to uard against too rapid descent of the standard, means being also provided on the said manually operated device for braking the jack in its descent. This last pro: vision guards against thetoo sudden descent of the jack when weighted.

With the foregoing and other objects in View, the invention consists in the details of construction and in the arrangement and combination of parts to be hereinafter more fully set forth and claimed.

In describing the invention in detail, reference will be had to the accompanying drawings forming part of this specification wherein like characters denote corresponding parts in the several views, in which Figure 1, is a vertical sectional View of a jack'embodying the invention; Fig. 2, illustrates a side elevation of the nut member of the jack with the ball race indicated in dotted lines; Fig. 8, is a detail view of the escapement mechanism and thebrake; Fig. 4, is an' enlarged detail View of the nut showing the race way and the balls therein; Fig. 5, is a top planview thereof; and Fig.

brake, the operating sleeve being omitted.

In these drawings A, denotes a base; B, a casin having its upper end supporting a nut The. nut C, vhas the ball race a, therein which extends and has two extensions 'C, C communicating with the interior of the nut and adapted to convey the balls I), which travel in the ball race, into the spaces between the threads of the nut.-

By reason of the. fact that the spirally of the nut ball race 0, the nut C, a channel is formed, which permits the application of the balls thereto. This openmg in the nut is closed, however,'by means of a sleeve secured to the nut C, and hence the said sleeve is interposed between the nut C, and the standard. It follows, that when i is desired to remove or apply the balls i101 ball race, the sleeve C may be removed an access may be had to the ball race throng the opening in the side of the nut O.

A screw E, is applied to the interior of. the nut and has screw threads fitted to the threads of the nut C, the contacting portions of the said t reads being curved as shown at C. This onstruction of the contacting surfaces of the threads is for the purpose of minimizing the friction and adding strength and durability to the structure. The surfaces of the threads engaged by the balls are approximately at right angles to the nut and bolt respectively, and the space between the surfaces is 4 diameter of the balls which travel therein.

The head F, of the jack is threaded in a sleeve G, and said sleeve is slidable on the standard B.' The upper end of the screw E, is reduced in diameter, and has a plate H,

fitted thereto, which plate lies in a recess of the bearing head F. The ported on balls I, which run in ball ways in the bearing block J, and by this arrangement, the screw E, and bearing block J, may rotate with relation to theplate H, the said plate being supported on the balls regardless of the direction of travel of the screw. The lower end of the screw is provided with a collar K, which is designed to contact the lower end of the nut, to limit 'the upward iovement of the screw said collar is preferably in the form of a disk of such a size as ,tocontact the inner sides of the casing whereby the screw is steadied and prevented from wabbling or rocking.

The upper end of the screw E, is provided with a toothed wheel L, which meshes with Patented Sept. 6, 1910.

practically equal to the' plate H, is supa pinion M, on the shaft N, which shaft N,

is journaled in a bearing 0, which is secured to and travels with the sleeve G, as

it is elevated by the screw. The bearin O,

has a depending portion P, in which a s a-ft' Q, is journaled and said shaft has a pinion R, meshing with a ear wheel S, on the shaft N. The shaft-Q, has an escapement wheel 's, which is engaged by an escapement lever T,-pivoted ona pm U, projecting from the depending portion P. The shaft Q, is also rovided with a brake wheel V, embraced y a friction band W, and through the con- IOQ trol of the'frictionband, the rotation of the friction wheel and the shaft is regulated.

The escapement lever T, is screw threaded and is provided with a Weight t, for regulating the rapidity of movement of the said escapement lever. The friction band has a threaded shank 'w, engaged by a threaded nut X, having an operating handle c. The threaded shank w, is run through an aperture in the friction band and the nut bears against the said apertured end and moves the friction band in relation to the friction wheel. The shaft N, has an operating handle Y, which is detachably applied to the said shaft.

The jack is provided with handles Z, piv oted to ears 2, projecting from the sides of the jack,

The friction band and escapcment mechanism is preferably interposed between the depending portion P, and the sleeve G, and the nut X, is likewise so interposed except for the operating handle which extends clear of the side of the depending portion 1.

It will be perfectly apparent, it is thought, that the operation of the lifting jack will be under the control of an operator, either for the purpose of raising the jack through the manipulation of the lever Y, or for the purpose of permitting the descent of the jack graduallythrough the control afforded by the friction and escapement mechanism.

I claim- V v 1. In a lifting jack, a base and easing, a sleeve slidable on the casing, a nut in the casing, a screw threaded in the nut, ahearing head in the end of the sleeve, a connection between the bearing head and screw whereby the bearing head is elevated, means for rotating the screw, and an escapement connected to the screw rotating means whereby the movement of the screw rotating means -1s regulated.

2. In a lifting'jack, a base and easing, a sleeve slidable on the casing, a nut in the casing, a screw threaded in the nut, a bearing head in the end of the sleeve, a connection between the bearing head and screw whereby the bearing head iselevated, a shaft for rotating the screw, a rotating member geared to the shaft, and an escapement for controlling the rotating member.

p 3. in a lifting jack, a base and easing, a sleeve slidable on the casing, a nut in the casing, a screw threaded in the nut, a bearing head in the end of the sleeve, :1 connection between the bearing head and screw whereby the bearing head is elevated, a shaft for rotating the screw, a rotating member geared to the shaft, a brake, and an adjustable escapement for regulating the movement of the rotating member.

4. In a lifting jack, a base and easing, a sleeve slidable on the casing,-a nut in the casing, a screw threaded in the nut, a bear-. ing head in the end of the sleeve, a connection between the bearing head and screw whereby the bearing head is elevated, a shaft for rotating the screw, a second shaft geared to thefirst mentioned shaft, an'escapement wheel and a friction wheel on the second shaft, a friction band on the friction wheel,

means for adjusting the friction band, and

an escapemcnt operating in conjunction with the escapement wheel.

'5. In a lifting jack, the combination with 51 base, and easing, a sleeve slidable on the casing, a nut in the casing, said nut having a channel adapted to receive balls, a screw threaded in the nut, and a bearing head in the end of the sleeve, of a connection between the bearing head and the screw whereby said head is elevated, means for rotating the screw, a rotating member geared to said means, a brake, and an esca ement for regulating the movement of said rotating member.

(3. in a lifting jack, a base and easing, a sleeve slidable on the casing, a nut in the casing, a screw threaded in the nut, a hearing head in the end of the sleeve, a connection between the bearing head and screw whereby the bearing head is elevated, a bearing mounted on .said casing, a shaft journaled therein adapted to rotate said screw, a gear on said shaft, said bearing havmg a de ending portion, a shaft journaled in said epending portion, apinion on said shaft meshing with saidgear, an escapement wheel on said shaft, and an escapement pivoted onsaid depending portion and adapted to regulate said escapement wheel. In testimony whereof, I afiix my signature in the presence of two Witnesses. I

' CALVIN T. STARBUCK. Witnesses L; J. Haney, J12, E. l). S'IARBUOK. 

